Embodiments herein generally relate to scanner registration (alignment) systems and methods and more particularly to systems and methods the provide notification of a need to re-register the scanner and document handler.
In a scanning system, such as a constant velocity transport (CVT) system with electronic registration, the mechanical registration is not tightly controlled but is adjusted in real time by the electronics using edge data detected from the page. For example, U.S. Pat. No. 4,511,242 (which is fully incorporated herein by reference) teaches the use of a reference pattern on a master image receiving sheet with a reference pattern on an original master in order to easily generate correction factors representative of the spatial difference and utilizing those correction factors to electronically control the relative position of receiving sheets and the image so that the sheets are fed to the processing station in synchronism with the latent image on the photoreceptor. In that manner, precision adjustment of mechanical parts is eliminated. Additionally, a feedback apparatus can be added so that wear within the system can be automatically compensated and any other factors causing dynamic misalignment can be compensated.
In order to set limits on the expected location of the page, the machine is run through a series of setup routines to determine the nominal fast scan and slow scan registration locations as well as a slow scan speed correction. Based on mechanical and paper tolerances a window of expected locations can be set. If the actual location of the paper drifts outside of the expected window, misregistration and image loss will occur.
For example, U.S. Pat. No. 5,748,293 (which is fully incorporated herein by reference) discloses belts that are shown at a small distance “t” spaced above the platen glass. This distance “t” represents a tolerance stack-up distance between the platen glass and the belts for when a sheet is present therebetween. A variation in this tolerance stack-up distance “t” between the platen glass and the document handler can cause document misfeeding or a skewed or mis-registered position of the document relative to the platen glass, which can result in skewed or mis-registered copies. This tolerance stack-up distance “t” is dependent on a number of factors or parameters, including, for example, the extent of wear on the belts and the weight and/or backing plate or rollers spring pressure and/or weight with which the belts are biased downwardly on a document overlying the platen glass.
Over time, parts wear and other factors can cause the nominal registration and magnification error of the manual document glass (platen) and the document handler of a scanning system to change. A service call for misregistration can be initiated when the customer starts seeing misregistration and image loss on scanned jobs. However, with the embodiments disclosed herein, a maintenance call could be made before the customer notices a problem, or a trained user could be instructed to run the setup themselves.